Sound-As Apalach said, the scotty base is already drilled. I thru bolted the base with SS bolts and nylock nuts (from Lowes). The regular scotty base can be mounted sideways or strait up and holes/fittings for the holder are already in each mount. When I use my fishfinder, it occupies that holder and I use the rearmost mount in the center consol for my fishing rod.
Thanks guys. I took a ride to my local yak dealer and noticed just that when I really looked at it close enough. It's certainly a nice option with limited space, as I have a fishfinder, GPS, and another rod holder already occupying the center console on my Quest.